/Engine/Source/Runtime/Engine/Public/PluginBlueprintLibrary.h
Get the list of extra directories that are recursively searched for plugins (aside from the engine and project plugin directories).
The additional filesystem plugin search paths.
static [TArray](API\Runtime\Core\Containers\TArray)< [FString](API\Runtime\Core\Containers\FString) > GetAdditionalPluginSearchPaths()